A person who is not a dedicated fan of a sports team. They only watch a game if it peaks their interest.

In most cases fair weather fans are bandwagoners who join in on the hype of a team or sporting event. Examples of this are: The Superbowl, The World Series, and Playoffs in general.

In other cases fair weather fans are people who just watch the sport or certain games when 'the weather is right'(when they feel like it). These fans are not characterized as bandwagoners because they have been fans of the sport/team before the hype and or big game (ex. Superbowl).

A Fair weather fan will usually tune in to watch big games such as: The Superbowl, The World Series, and Playoff games etc.

This is an example of a fair weather fan that is also a bandwagoner:
My brother: The World Series on tonight! I can't wait!
Me: Since when did you like baseball?
My brother: I don't, but its the World Series!

This is an example of a fair weather fan:
My friend: Celtics are on tonight.
Me: Since when do you watch basketball?
My friend: I watch it occasionally, plus its the playoffs.

A fan of a sports team who only shows support when the team is doing well. During hard times they usually bandwagon other teams. They basically have no real loyalty to the team, but still manage to get better seats than you at the game. Strangely they mysteriously vanish at the first sign of trouble.

Fair weather fan: "OMG what a comeback! That was amazing!"

Regular fan: "How would you know? You left right when Favre threw the pick six in the 2nd and if I recall you didn't even start rooting for Green Bay until 2 weeks ago."

Fair weather fan: "... GO PACK!"

(After the playoff game the fair weather fan immediately became a Pats fan and stowed all Packer memorabilia away.)

New Dats. A sickening majority of 2009-2010 Saints Fans who couldn't stand the saints or the NFL for most of the season. The last 8 weeks this fan has bought 10 shirts, a jersey and hotel room in the quarter to proclaim how much they love the saints and leech off the joy felt by the who dats. In other words they are about as cool as a fanny pack.

New Dat: Stand up and get what
Who Dat: it is Stand up and get Crunk
Who Dat 2: who in the fuck is that?
Who Dat: Another fucking New Dat
Who Dat2: Where were all of them 8 weeks ago?
Who Dat: Leaching of the corndogs at LSU. Don't worry they won't be here long.
Who Dat 2: Good I hate the fair weather fans, they are fucking useless and they are raising the ticket prices.

People who only support sports teams when they are doing well ie when the "weather is fair." If their team is losing, they don't claim to be a fan, but when their team is winning, they are obnoxious to the highest degree.

"Florida (Gators) are such fair weather fans, you don't hear shit from them unless they're winning."

"Georgia (Bulldogs) are the opposite of fair weather fans, they are DAWGS to the core, win or lose."